<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    var a = 10;
    var b = 0;
    if (b==0){
        alert('aa')
    }
    var c  = a / b;
    // 表达式 * 表达式
    console.log(c);     //isFinite(c)
    console.log(isFinite(c))
</script>
</body>
</html>